1. Field of the Invention
The subject invention relates to methods and apparatus for recording and reproducing video information and, more specifically, to such methods and apparatus wherein theft, unauthorized reproduction and/or unauthorized copying of video recordings are substantially impeded.
2. Description of the Prior Art
The problem of theft, unauthorized reproduction and/or unauthorized copying of video recordings has become acute with the proliferation of video recording and/or reproduction equipment.
Unfortunately, video signal scrambling techniques of the type employed in video signal transmission are not suitable to adaptation to the video recording field, as such techniques tend to degrade the recorded and reproduced video signal, render the recording and reproduction equipment too complex and expensive and increase down time and service problems.
By way of example, reference is made to the television scrambling system disclosed in U.S. Pat. No. 3,460,161, by P. J. Waller et al, issued Aug. 5, 1969. In that and similar prior-art systems, scrambling is practiced on the television signal itself, by deliberately degrading the horizontal synchronization signal and introducing spurious signals that will disturb the video synchronization process in the receiver. Practice of that system also involves a distrubance of the video information, in that the picture waveforms are shifted in time and cut off on one side.